Atmospheric histories and global emissions of halons H-1211 (CBrClF 2 ), H-1301 (CBrF 3 ), and H-2402 (CBrF 2 CBrF 2 )

We report ground-based atmospheric measurements and emission estimates for the halons H-1211 (CBrClF₂), H-1301 (CBrF₃), and H-2402 (CBrF₂CBrF₂) from the AGAGE (Advanced Global Atmospheric Gases Experiment) and the National Oceanic and Atmospheric Administration global networks. We also include results from archived air samples in canisters and from polar firn in both hemispheres, thereby deriving an atmospheric record of nearly nine decades (1930s to present). All three halons were absent from the atmosphere until ~1970, when their atmospheric burdens started to increase rapidly. In recent years H-1211 and H-2402 mole fractions have been declining, but H-1301 has continued to grow. High-frequency observations show continuing emissions of H-1211 and H-1301 near most AGAGE sites. For H-2402 the only emissions detected were derived from the region surrounding the Sea of Japan/East Sea. Based on our observations, we derive global emissions using two different inversion approaches. Emissions for H-1211 declined from a peak of 11 kt yr⁻¹ (late 1990s) to 3.9 kt yr⁻¹ at the end of our record (mean of 2013–2015), for H-1301 from 5.4 kt yr⁻¹ (late 1980s) to 1.6 kt yr⁻¹, and for H-2402 from 1.8 kt yr⁻¹ (late 1980s) to 0.38 kt yr⁻¹. Yearly summed halon emissions have decreased substantially; nevertheless, since 2000 they have accounted for ~30% of the emissions of all major anthropogenic ozone depletion substances, when weighted by ozone depletion potentials.

Convention revising the General Act of Berlin, February 26, 1885, and the General Act and Declaration of Brussels, July 2, 1890 : signed at Saint-Germain-en-Laye, September 10, 1919.

"Presented to Parliament by Command of His Majesty."

The parochial registers of Saint Germain-en-Laye. Jacobite extracts of births, marriages and deaths,

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Quadrennial address of the bishops of the Colored Methodist Episcopal Church to the fourteenth session of the General Conference : held in Saint Louis, Missouri, May third, one thousand nine hundred and twenty two.

Signed at end: Isaac Lane (retired). Robert Simeon Williams. Elias Cottrell. Charles Henry Phillips. Randall Albert Carter. Nelson Caldwell Cleaves.

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The most holy trinosophia of the Comte de Saint-Germain,

Initials.

Saint Columba : Apostle of Caledonia /

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The martyrdom and miracles of Saint George of Cappadocia.

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